[5]“In O. sensibilis the sori are borne on the middle of the vein, and consist of a tough cylindrical receptacle, three or four diameters in height, bearing sporangia thickly all over its surface, and covered when young by a delicate hood-like indusium, attached half-way or more around the base of the receptacle on the inferior side, and having the crenulate-margined opening toward the apex of the segment. At an early stage the blackberry-shaped sorus is almost entirely covered by the indusium, which resembles a closely drawn cowl, but with the growth of the sporangia it is thrown back, or rent, and soon disappears, the sori becoming confluent. The receptacle is very persistent, and may be seen, covered with the stalks of the sporangia, in the dried last-year’s fertile fronds, which are always found where the plant grows.”

Transcriber’s Notes